Computers in Biology and Medicine 113 (2019) 103414 Contents lists available at ScienceDirect Computers in Biology and Medicine journal homepage: www.elsevier.com/locate/compbiomed Pharmacoinformatics-based identification of potential bioactive compounds against Ebola virus protein VP24 T ∗ Samuel K. Kwofiea,b,c, , Emmanuel Bronia, Joshua Teyea, Erasmus Quansahd, Ibrahim Issaha, Michael D. Wilsonc,d, Whelton A. Miller IIIc,e, Elvis K. Tiburua,b, Joseph H.K. Bonneyf a Department of Biomedical Engineering, School of Engineering Sciences, College of Basic & Applied Sciences, University of Ghana, PMB LG 77, Legon, Accra, Ghana b West African Center for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana c Department of Medicine, Loyola University Medical Center, Maywood, IL, 60153, USA d Department of Parasitology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences (CHS), University of Ghana, P.O. Box LG 581, Legon, Accra, Ghana e Department of Chemical and Biomolecular Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA f Department of Virology, Noguchi Memorial Institute for Medical Research (NMIMR), College of Health Sciences (CHS), University of Ghana, P.O. Box LG 581, Legon, Accra, Ghana ARTICLE INFO ABSTRACT Keywords: Background: The impact of Ebola virus disease (EVD) is devastating with concomitant high fatalities. Currently, Ebola virus protein VP24 various drugs and vaccines are at different stages of development, corroborating the need to identify new Virtual screening therapeutic molecules. The VP24 protein of the Ebola virus (EBOV) plays a key role in the pathology and Molecular docking replication of the EVD. The VP24 protein interferes with the host immune response to viral infections and Molecular dynamics promotes nucleocapsid formation, thus making it a viable drug target. This study sought to identify putative lead Ebola virus inhibitors compounds from the African flora with potential to inhibit the activity of the EBOV VP24 protein using phar- African natural products macoinformatics and molecular docking. Methods: An integrated library of 7675 natural products originating from Africa obtained from the AfroDB and NANPDB databases, as well as known inhibitors were screened against VP24 (PDB ID: 4M0Q) utilising AutoDock Vina after energy minimization using GROMACS. The top 19 compounds were physicochemically and phar- macologically profiled using ADMET Predictor™, SwissADME and DataWarrior. The mechanisms of binding between the molecules and EBOV VP24 were characterised using LigPlot+. The performance of the molecular docking was evaluated by generating a receiver operating characteristic (ROC) by screening known inhibitors and decoys against EBOV VP24. The prediction of activity spectra for substances (PASS) and machine learning- based Open Bayesian models were used to predict the anti-viral and anti-Ebola activity of the molecules, re- spectively. Results: Four natural products, namely, ZINC000095486070, ZINC000003594643, ZINC000095486008 and sarcophine were found to be potential EBOV VP24-inhibitiory molecules. The molecular docking results showed that ZINC000095486070 had high binding affinity of −9.7 kcal/mol with EBOV VP24, which was greater than those of the known VP24-inhibitors used as standards in the study including Ouabain, Nilotinib, Clomiphene, Torimefene, Miglustat and BCX4430. The area under the curve of the generated ROC for evaluating the per- formance of the molecular docking was 0.77, which was considered acceptable. The predicted promising mo- lecules were also validated using induced-fit docking with the receptor using Schrödinger and molecular me- chanics Poisson-Boltzmann surface area (MM-PBSA) calculations. The molecules had better binding mechanisms and were pharmacologically profiled to have plausible efficacies, negligible toxicity as well as suitable for de- signing anti-Ebola scaffolds. ZINC000095486008 and sarcophine (NANPDB135) were predicted to possess anti- viral activity, while ZINC000095486070 and ZINC000003594643 to be anti-Ebola compounds. Conclusion: The identified compounds are potential inhibitors worthy of further development as EBOV bio- therapeutic agents. The scaffolds of the compounds could also serve as building blocks for designing novel Ebola inhibitors. ∗ Corresponding author. Department of Biomedical Engineering, School of Engineering Sciences, College of Basic & Applied Sciences, University of Ghana, PMB LG 77, Legon, Accra, Ghana. E-mail address: skkwofi[email protected] (S.K. Kwofie). https://doi.org/10.1016/j.compbiomed.2019.103414 Received 18 March 2019; Received in revised form 23 August 2019; Accepted 24 August 2019 Available online 28 August 2019 0010-4825/ © 2019 Published by Elsevier Ltd. fi S.K. Kwo e, et al. Computers in Biology and Medicine 113 (2019) 103414 Fig. 1. Graphical representation of the schematic workflow adopted in this study. The methods included pre-filtering of ligands using toxicity, Lipinski's and Veber's rules. Molecular docking and dynamics simulations, as well as antiviral activity predictions were used to support potential lead identification. LigPlot+ was used to determine the protein ligand interaction profiles (PLIP) whiles pharmacokinetics profiling was undertaken by determining absorption, distribution, metabolism, excretion and toxicity (ADMET). 2 fi S.K. Kwo e, et al. Computers in Biology and Medicine 113 (2019) 103414 1. Introduction drug repurposing approach involved the screening of approved drugs to aid in the identification of novel inhibitors of EBOV [21,27]. Ad- Ebola virus disease (EVD) is a viral haemorrhagic fever caused by ditionally, antiviral screening of multiple compounds using live EBOV Ebola viruses which affects humans and other primates [1,2]. Like other has been reported [28]. filoviruses, Ebola virus (EBOV) replicates very efficiently in many cells, Natural product-derived compounds are drug-like molecules which giving rise to an appreciable number of the virus in cells of the serve as rich sources of scaffolds for the discovery of novel drug leads mononuclear phagocyte system (MPS) and others including liver cells, [29]. Also, natural products have been reported to be rich in structural fibroblasts and adrenal gland cells [3]. EBOV is reported to be trans- and chemical diversity [30]. In silico screening of natural products with mitted to humans through direct contact with blood, mucous mem- therapeutic effects against EBOV have been reported [31]. Curcumin, branes or through skin contact. The disease is associated with a high curcuminoids and tetrahydrocurcumin are bioactive compounds of risk of death, killing an average of about 50% of those infected with the natural product origin which have shown potential anti-viral activity highest death rate being up to 90% [4]. against EBOV proteins [32,33]. Previously, A total of 2020 Indonesian The World Health Organization (WHO) reported a total of 24 Ebola natural products were screened against Ebola VP24 receptor and Cy- outbreaks involving 1716 cases from 1976 to 2013. Also, the largest cloartocarpin was suggested as an anti-Ebola lead with the least Gibbs outbreak ever recorded was the epidemic in West Africa, mostly in free binding energy of −7.4847 kcal/mol [34]. Liberia, Sierra Leone and Guinea from December 2013 to January 2016, Pharmacoinformatics has evolved as one of the most cost-effective claiming a little over 11,000 lives out of about 28,000 reported cases and reliable techniques to discover novel leads [35–37]. In silico iden- [5,6]. Even though, the end of the EVD outbreak in West Africa was tification of potential EBOV inhibitors targeting the different viral declared in August 2018, it has re-emerged in the Democratic Republic proteins using molecular docking and quantitative structure–activity of Congo. As at 1st May 2019, the total cases had reached 1510 (1444 relationships (QSAR) studies have been reported [23,32,38–41]. confirmed) in the DRC with 994 deaths of which 928 were confirmed Therefore, the identification of new bioactive compounds via in silico [7]. Recent studies have shown EVD reservoir in bats to be widespread drug design is vital in unravelling of novel leads which have the po- with the identification of Bombali virus in the free-tailed bats (Family: tential to inhibit the activity of VP24. The African flora remains an Molossidae) in Sierra Leone and the discovery of a new genus of the untapped reservoir of new drug candidates for combating various kinds filovirus the Mengla virus in Rousettus bats (Family: Megabats) [8,9]. of diseases [42,43] and has been reported to have a diverse set of The EBOV is a single-stranded RNA virus which encodes seven natural products with viable anti-viral activities [44]. The African proteins; nucleoproteins (NP), glycoprotein (GP), polymerase (L), VP24, continent is rich in biodiversity [45] and this can be exploited to pro- VP30, VP35 and VP40. The VP24 and VP35 structural proteins of EBOV duce novel drug candidates from its natural sources. are believed to play a very important role of interfering with the human The study sought to identify potential natural product-derived immune system's response to viral infections [10]. The VP24 protein is EBOV VP24 protein inhibitory compounds by virtual screening of an integral in the formation of nucleocapsid (NC) and also a secondary integrated African natural product library [46,47].